This is a difficult one. I dont think a helicoil can be fitted without removing the head -- still I suppose one has plenty of time to do this at the moment. It might be ok for another 10k miles but I would be worried about running it as is and it will haveto be done some time. I know it's too late to help your problem but I always remove the plugs as soon as I get any car (new or used), lubricate the plug threads with ultra high temp ceramic grease (some people use Coppersip) and refit them. It's so easy to damage alloy heads, particularly with the very narrow bodies of some modern spark plugs. You might be able to fit the helicoil with the head in place and suck the swarf from the combustion chamber with a pipe on a Hoover but I've never done it. On another matter I'm signed up for the Remparts this Sept but God knows if it will go ahead.
